I've seen people do his civilian look. It can be spotted if you do a wig or your hair just right, have the right glasses, and maybe have pictures of his little girl to carry around with you. It works best in a full FMA group, but it can work alone. It's also a good cosplay to do when you want to be casual and comfortable and possibly not get stopped every two feet to take pictures. It's like an incognito cosplay.

Most people won't know who you are, more than likely. I personally wouldn't. He's not seen very often in his casual attire and it blends right in with normal street clothes. So if you want to be recognized use his military uniform.